usr/src/man/man5/eqn.5 - illumos-gate - Gitiles

 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
 .\" purpose with or without fee is hereby granted, provided that the above
 .\" copyright notice and this permission notice appear in all copies.
 .\"
 .\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 .\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 .\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 .\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 .\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 .\"
 .\"
 .\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\" Copyright 2012 Nexenta Systems, Inc. All rights reserved.
 .\"
 .Dd Jul 19, 2014
 .Dt EQN 5
 .Os
 .Sh NAME
 .Nm eqn
 .Nd eqn language reference for mandoc
 .Sh DESCRIPTION
 The
 .Nm eqn
 language is an equation-formatting language.
 It is used within
 .Xr mdoc 5
 and
 .Xr man 5
 .Ux
 manual pages.
 It describes the
 .Em structure
 of an equation, not its mathematical meaning.
 This manual describes the
 .Nm
 language accepted by the
 .Xr mandoc 1
 utility, which corresponds to the Second Edition eqn specification (see
 .Sx SEE ALSO
 for references).
 .Pp
 Equations within
 .Xr mdoc 5
 or
 .Xr man 5
 documents are enclosed by the standalone
 .Sq \&.EQ
 and
 .Sq \&.EN
 tags.
 Equations are multi-line blocks consisting of formulas and control
 statements.
 .Sh EQUATION STRUCTURE
 Each equation is bracketed by
 .Sq \&.EQ
 and
 .Sq \&.EN
 strings.
 .Em Note :
 these are not the same as
 .Xr roff 5
 macros, and may only be invoked as
 .Sq \&.EQ .
 .Pp
 The equation grammar is as follows, where quoted strings are
 case-sensitive literals in the input:
 .Bd -literal -offset indent
 eqn     : box | eqn box
 box     : text
         | \*q{\*q eqn \*q}\*q
         | \*qdefine\*q text text
         | \*qndefine\*q text text
         | \*qtdefine\*q text text
         | \*qgfont\*q text
         | \*qgsize\*q text
         | \*qset\*q text text
         | \*qundef\*q text
         | box pos box
         | box mark
         | \*qmatrix\*q \*q{\*q [col \*q{\*q list \*q}\*q ]*
         | pile \*q{\*q list \*q}\*q
         | font box
         | \*qsize\*q text box
         | \*qleft\*q text eqn [\*qright\*q text]
 col     : \*qlcol\*q | \*qrcol\*q | \*qccol\*q | \*qcol\*q
 text    : [^space\e\*q]+ | \e\*q.*\e\*q
 pile    : \*qlpile\*q | \*qcpile\*q | \*qrpile\*q | \*qpile\*q
 pos     : \*qover\*q | \*qsup\*q | \*qsub\*q | \*qto\*q | \*qfrom\*q
 mark	: \*qdot\*q | \*qdotdot\*q | \*qhat\*q | \*qtilde\*q | \*qvec\*q
         | \*qdyad\*q | \*qbar\*q | \*qunder\*q
 font    : \*qroman\*q | \*qitalic\*q | \*qbold\*q | \*qfat\*q
 list    : eqn
         | list \*qabove\*q eqn
 space   : [\e^~ \et]
 .Ed
 .Pp
 White-space consists of the space, tab, circumflex, and tilde
 characters.
 If within a quoted string, these space characters are retained.
 Quoted strings are also not scanned for replacement definitions.
 .Pp
 The following text terms are translated into a rendered glyph, if
 available: alpha, beta, chi, delta, epsilon, eta, gamma, iota, kappa,
 lambda, mu, nu, omega, omicron, phi, pi, psi, rho, sigma, tau, theta,
 upsilon, xi, zeta, DELTA, GAMMA, LAMBDA, OMEGA, PHI, PI, PSI, SIGMA,
 THETA, UPSILON, XI, inter (intersection), union (union), prod (product),
 int (integral), sum (summation), grad (gradient), del (vector
 differential), times (multiply), cdot (centre-dot), nothing (zero-width
 space), approx (approximately equals), prime (prime), half (one-half),
 partial (partial differential), inf (infinity), >> (much greater), <<
 (much less), \-> (left arrow), <\- (right arrow), += (plus-minus), !=
 (not equal), == (equivalence), <= (less-than-equal), and >=
 (more-than-equal).
 .Pp
 The following control statements are available:
 .Bl -tag -width Ds
 .It Cm define
 Replace all occurrences of a key with a value.
 Its syntax is as follows:
 .Pp
 .D1 define Ar key cvalc
 .Pp
 The first character of the value string,
 .Ar c ,
 is used as the delimiter for the value
 .Ar val .
 This allows for arbitrary enclosure of terms (not just quotes), such as
 .Pp
 .D1 define Ar foo 'bar baz'
 .D1 define Ar foo cbar bazc
 .Pp
 It is an error to have an empty
 .Ar key
 or
 .Ar val .
 Note that a quoted
 .Ar key
 causes errors in some
 .Nm
 implementations and should not be considered portable.
 It is not expanded for replacements.
 Definitions may refer to other definitions; these are evaluated
 recursively when text replacement occurs and not when the definition is
 created.
 .Pp
 Definitions can create arbitrary strings, for example, the following is
 a legal construction.
 .Bd -literal -offset indent
 define foo 'define'
 foo bar 'baz'
 .Ed
 .Pp
 Self-referencing definitions will raise an error.
 The
 .Cm ndefine
 statement is a synonym for
 .Cm define ,
 while
 .Cm tdefine
 is discarded.
 .It Cm gfont
 Set the default font of subsequent output.
 Its syntax is as follows:
 .Pp
 .D1 gfont Ar font
 .Pp
 In
 .Xr mandoc 1 ,
 this value is discarded.
 .It Cm gsize
 Set the default size of subsequent output.
 Its syntax is as follows:
 .Pp
 .D1 gsize Ar size
 .Pp
 The
 .Ar size
 value should be an integer.
 .It Cm set
 Set an equation mode.
 In
 .Xr mandoc 1 ,
 both arguments are thrown away.
 Its syntax is as follows:
 .Pp
 .D1 set Ar key val
 .Pp
 The
 .Ar key
 and
 .Ar val
 are not expanded for replacements.
 This statement is a GNU extension.
 .It Cm undef
 Unset a previously-defined key.
 Its syntax is as follows:
 .Pp
 .D1 define Ar key
 .Pp
 Once invoked, the definition for
 .Ar key
 is discarded.
 The
 .Ar key
 is not expanded for replacements.
 This statement is a GNU extension.
 .El
 .Sh COMPATIBILITY
 This section documents the compatibility of
 .Xr mandoc 1
 .Nm
 and the
 .Xr troff 1
 .Nm
 implementation (including GNU troff).
 .Pp
 .Bl -dash -compact
 .It
 The text string
 .Sq \e\*q
 is interpreted as a literal quote in
 .Xr troff 1 .
 In
 .Xr mandoc 1 ,
 this is interpreted as a comment.
 .It
 In
 .Xr troff 1 ,
 The circumflex and tilde white-space symbols map to
 fixed-width spaces.
 In
 .Xr mandoc 1 ,
 these characters are synonyms for the space character.
 .It
 The
 .Xr troff 1 ,
 implementation of
 .Nm
 allows for equation alignment with the
 .Cm mark
 and
 .Cm lineup
 tokens.
 .Xr mandoc 1
 discards these tokens.
 The
 .Cm back Ar n ,
 .Cm fwd Ar n ,
 .Cm up Ar n ,
 and
 .Cm down Ar n
 commands are also ignored.
 .El
 .Sh SEE ALSO
 .Xr mandoc 1 ,
 .Xr man 5 ,
 .Xr mandoc_char 5 ,
 .Xr mdoc 5 ,
 .Xr roff 5
 .Rs
 .%A Brian W. Kernighan
 .%A Lorinda L. Cherry
 .%T System for Typesetting Mathematics
 .%J Communications of the ACM
 .%V 18
 .%P 151\(en157
 .%D March, 1975
 .Re
 .Rs
 .%A Brian W. Kernighan
 .%A Lorinda L. Cherry
 .%T Typesetting Mathematics, User's Guide
 .%D 1976
 .Re
 .Rs
 .%A Brian W. Kernighan
 .%A Lorinda L. Cherry
 .%T Typesetting Mathematics, User's Guide (Second Edition)
 .%D 1978
 .Re
 .Sh HISTORY
 The eqn utility, a preprocessor for troff, was originally written by
 Brian W. Kernighan and Lorinda L. Cherry in 1975.
 The GNU reimplementation of eqn, part of the GNU troff package, was
 released in 1989 by James Clark.
 The eqn component of
 .Xr mandoc 1
 was added in 2011.
 .Sh AUTHORS
 This
 .Nm
 reference was written by
 .An Kristaps Dzonsons ,
 .Mt kristaps@bsd.lv .
	.\"
	.\" Permission to use, copy, modify, and distribute this software for any
	.\" purpose with or without fee is hereby granted, provided that the above
	.\" copyright notice and this permission notice appear in all copies.
	.\"
	.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
	.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	.\"
	.\"
	.\" Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
	.\" Copyright 2012 Nexenta Systems, Inc. All rights reserved.
	.\"
	.Dd Jul 19, 2014
	.Dt EQN 5
	.Os
	.Sh NAME
	.Nm eqn
	.Nd eqn language reference for mandoc
	.Sh DESCRIPTION
	The
	.Nm eqn
	language is an equation-formatting language.
	It is used within
	.Xr mdoc 5
	and
	.Xr man 5
	.Ux
	manual pages.
	It describes the
	.Em structure
	of an equation, not its mathematical meaning.
	This manual describes the
	.Nm
	language accepted by the
	.Xr mandoc 1
	utility, which corresponds to the Second Edition eqn specification (see
	.Sx SEE ALSO
	for references).
	.Pp
	Equations within
	.Xr mdoc 5
	or
	.Xr man 5
	documents are enclosed by the standalone
	.Sq \&.EQ
	and
	.Sq \&.EN
	tags.
	Equations are multi-line blocks consisting of formulas and control
	statements.
	.Sh EQUATION STRUCTURE
	Each equation is bracketed by
	.Sq \&.EQ
	and
	.Sq \&.EN
	strings.
	.Em Note :
	these are not the same as
	.Xr roff 5
	macros, and may only be invoked as
	.Sq \&.EQ .
	.Pp
	The equation grammar is as follows, where quoted strings are
	case-sensitive literals in the input:
	.Bd -literal -offset indent
	eqn : box \| eqn box
	box : text
	\| \q{\q eqn \q}\q
	\| \qdefine\q text text
	\| \qndefine\q text text
	\| \qtdefine\q text text
	\| \qgfont\q text
	\| \qgsize\q text
	\| \qset\q text text
	\| \qundef\q text
	\| box pos box
	\| box mark
	\| \qmatrix\q \q{\q [col \q{\q list \q}\q ]*
	\| pile \q{\q list \q}\q
	\| font box
	\| \qsize\q text box
	\| \qleft\q text eqn [\qright\q text]
	col : \qlcol\q \| \qrcol\q \| \qccol\q \| \qcol\q
	text : [^space\e\q]+ \| \e\q.\e\q
	pile : \qlpile\q \| \qcpile\q \| \qrpile\q \| \qpile\q
	pos : \qover\q \| \qsup\q \| \qsub\q \| \qto\q \| \qfrom\q
	mark : \qdot\q \| \qdotdot\q \| \qhat\q \| \qtilde\q \| \qvec\q
	\| \qdyad\q \| \qbar\q \| \qunder\q
	font : \qroman\q \| \qitalic\q \| \qbold\q \| \qfat\q
	list : eqn
	\| list \qabove\q eqn
	space : [\e^~ \et]
	.Ed
	.Pp
	White-space consists of the space, tab, circumflex, and tilde
	characters.
	If within a quoted string, these space characters are retained.
	Quoted strings are also not scanned for replacement definitions.
	.Pp
	The following text terms are translated into a rendered glyph, if
	available: alpha, beta, chi, delta, epsilon, eta, gamma, iota, kappa,
	lambda, mu, nu, omega, omicron, phi, pi, psi, rho, sigma, tau, theta,
	upsilon, xi, zeta, DELTA, GAMMA, LAMBDA, OMEGA, PHI, PI, PSI, SIGMA,
	THETA, UPSILON, XI, inter (intersection), union (union), prod (product),
	int (integral), sum (summation), grad (gradient), del (vector
	differential), times (multiply), cdot (centre-dot), nothing (zero-width
	space), approx (approximately equals), prime (prime), half (one-half),
	partial (partial differential), inf (infinity), >> (much greater), <<
	(much less), \-> (left arrow), <\- (right arrow), += (plus-minus), !=
	(not equal), == (equivalence), <= (less-than-equal), and >=
	(more-than-equal).
	.Pp
	The following control statements are available:
	.Bl -tag -width Ds
	.It Cm define
	Replace all occurrences of a key with a value.
	Its syntax is as follows:
	.Pp
	.D1 define Ar key cvalc
	.Pp
	The first character of the value string,
	.Ar c ,
	is used as the delimiter for the value
	.Ar val .
	This allows for arbitrary enclosure of terms (not just quotes), such as
	.Pp
	.D1 define Ar foo 'bar baz'
	.D1 define Ar foo cbar bazc
	.Pp
	It is an error to have an empty
	.Ar key
	or
	.Ar val .
	Note that a quoted
	.Ar key
	causes errors in some
	.Nm
	implementations and should not be considered portable.
	It is not expanded for replacements.
	Definitions may refer to other definitions; these are evaluated
	recursively when text replacement occurs and not when the definition is
	created.
	.Pp
	Definitions can create arbitrary strings, for example, the following is
	a legal construction.
	.Bd -literal -offset indent
	define foo 'define'
	foo bar 'baz'
	.Ed
	.Pp
	Self-referencing definitions will raise an error.
	The
	.Cm ndefine
	statement is a synonym for
	.Cm define ,
	while
	.Cm tdefine
	is discarded.
	.It Cm gfont
	Set the default font of subsequent output.
	Its syntax is as follows:
	.Pp
	.D1 gfont Ar font
	.Pp
	In
	.Xr mandoc 1 ,
	this value is discarded.
	.It Cm gsize
	Set the default size of subsequent output.
	Its syntax is as follows:
	.Pp
	.D1 gsize Ar size
	.Pp
	The
	.Ar size
	value should be an integer.
	.It Cm set
	Set an equation mode.
	In
	.Xr mandoc 1 ,
	both arguments are thrown away.
	Its syntax is as follows:
	.Pp
	.D1 set Ar key val
	.Pp
	The
	.Ar key
	and
	.Ar val
	are not expanded for replacements.
	This statement is a GNU extension.
	.It Cm undef
	Unset a previously-defined key.
	Its syntax is as follows:
	.Pp
	.D1 define Ar key
	.Pp
	Once invoked, the definition for
	.Ar key
	is discarded.
	The
	.Ar key
	is not expanded for replacements.
	This statement is a GNU extension.
	.El
	.Sh COMPATIBILITY
	This section documents the compatibility of
	.Xr mandoc 1
	.Nm
	and the
	.Xr troff 1
	.Nm
	implementation (including GNU troff).
	.Pp
	.Bl -dash -compact
	.It
	The text string
	.Sq \e\*q
	is interpreted as a literal quote in
	.Xr troff 1 .
	In
	.Xr mandoc 1 ,
	this is interpreted as a comment.
	.It
	In
	.Xr troff 1 ,
	The circumflex and tilde white-space symbols map to
	fixed-width spaces.
	In
	.Xr mandoc 1 ,
	these characters are synonyms for the space character.
	.It
	The
	.Xr troff 1 ,
	implementation of
	.Nm
	allows for equation alignment with the
	.Cm mark
	and
	.Cm lineup
	tokens.
	.Xr mandoc 1
	discards these tokens.
	The
	.Cm back Ar n ,
	.Cm fwd Ar n ,
	.Cm up Ar n ,
	and
	.Cm down Ar n
	commands are also ignored.
	.El
	.Sh SEE ALSO
	.Xr mandoc 1 ,
	.Xr man 5 ,
	.Xr mandoc_char 5 ,
	.Xr mdoc 5 ,
	.Xr roff 5
	.Rs
	.%A Brian W. Kernighan
	.%A Lorinda L. Cherry
	.%T System for Typesetting Mathematics
	.%J Communications of the ACM
	.%V 18
	.%P 151\(en157
	.%D March, 1975
	.Re
	.Rs
	.%A Brian W. Kernighan
	.%A Lorinda L. Cherry
	.%T Typesetting Mathematics, User's Guide
	.%D 1976
	.Re
	.Rs
	.%A Brian W. Kernighan
	.%A Lorinda L. Cherry
	.%T Typesetting Mathematics, User's Guide (Second Edition)
	.%D 1978
	.Re
	.Sh HISTORY
	The eqn utility, a preprocessor for troff, was originally written by
	Brian W. Kernighan and Lorinda L. Cherry in 1975.
	The GNU reimplementation of eqn, part of the GNU troff package, was
	released in 1989 by James Clark.
	The eqn component of
	.Xr mandoc 1
	was added in 2011.
	.Sh AUTHORS
	This
	.Nm
	reference was written by
	.An Kristaps Dzonsons ,
	.Mt kristaps@bsd.lv .